7
• Discharge pressure in excess of
nominal conditions
• Too rapid acceleration or deceleration
of the drive system
• An increase in fluid viscosity
• Foreign particles impinging upon
pump internal components
• Increased friction due to a poorly
lubricating process fluid
The decoupling characteristic of mag-
nets can be a safety feature, preventing
inadvertent pump/motor overloads.
Magnets should be chosen so that their
decoupling torque is greater than the
pump input torque. This should include
any transient, starting, and stopping con-
ditions in addition to steady state values.
The decoupling torque can vary with
different fluids, temperatures, operating
pressures, and magnet sizes. Accurate
sizing of magnets for a specific
application requires precise knowledge of
several operating conditions. Check with
your Zenith representative to see which
9000-MD system is appropriate.
General Magnetic Coupling
Precautions
Both the inner and outer magnetic
rotors are very powerful.
Handle them with
caution.
Danger!
Persons with cardiac pacemakers
should stay at least 8 feet from the
magnetic product at all times.
Do not
position hands or fingers so
that they may become trapped between
the two magnetic rotors, or between one
magnet and a metal object.
Do not
position the magnets near one
another unless assembling the pump to the
system. Both rotors should be fastened to
their respective shafts before bringing
them into proximity.
Do not
place the magnets near any
electronic equipment or media that is
sensitive to magnetic fields ( computers,
diskettes, credit cards, etc.)
When storing and assembling the
magnetic coupling, make sure that no
small metallic fasteners, pieces or other
foreign objects adhere to the rotors or
barrier cap.
If the magnets de-couple, stop the
drive system for the pump immediately.
Determine the cause of the excessive
torque requirement and remedy the
problem prior to re-starting the system.
Care During
Operation
(cont.)
Key:
∆
P = Pressure (psi)
µ
= Viscosity (cp)
N = Speed (rpm)
0.00
0.001
0.01
0.1
1
10
100
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
∆
P/(
µ
•N)
Derating Factor
0.3 cc/rev
4.5 cc/rev
9.0 cc/rev
0.6 cc/rev
1.2 cc/rev
2.4 cc/rev
C-9000 Pump Performance
Graph 1
Inlet Pressure Loss (psi) = Viscosity(cps)
•
Displacement(cc/rev)
•
Shaft Speed(rpm)
•
[(Specific Gravity
•
W1)+W2]
Note:
This sizing procedure should be used as a
guideline for estimating pump type, pump size
and system requirements. Please consult Zenith to
confirm pump and system selection prior to placing
a purchase order.
Flowrate = pump capacity (cc/rev) x rpm x performance factor
WARNING
cc/rev
W1
W2
0.3
4.29E-06
2.32E-06
0.6
1.93E-06
2.47E-06
1.2
1.21E-06
2.77E-06
2.4
9.34E-07
3.38E-06
4.5
3.00E-07
3.46E-07
9.0
2.24E-07
4.19E-07
Table 1
